Event Alerting Through Actigraphy Embedded Within Electrocardiographic Data

ABSTRACT

Physiological monitoring can be provided through an actigraphy sensor imbedded into an electrocardiography monitor, which correlates movement and electrocardiographic data. Physiological monitoring can be provided through a wearable monitor that includes two components, a flexible extended wear electrode patch and a removable reusable monitor recorder. The wearable monitor sits centrally on the patient&#39;s chest along the sternum. The patient can place an electrode patch anywhere within the general region of the sternum. The occurrence of actigraphy events are monitored by the monitor recorder through an actigraphy sensor. Actigraphy becomes a recordable actigraphy event occurrence when the movement of the wearable monitor and, therefore, the patient, exceeds a certain criteria threshold of acceleration or deceleration as detected by the actigraphy sensor. Certain actigraphy event occurrences as recorded by the monitor recorder are considered to be actionable, that is, of sufficient importance to warrant flagging for further consideration to a following physician.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional patent application is a continuation-in-part ofU.S. patent application Ser. No. 14/080,717, filed Nov. 14, 2013,pending, and a continuation-in-part of U.S. patent application Ser. No.14/080,725, filed Nov. 14, 2013, pending, and further claims priorityunder 35 U.S.C. §119(e) to U.S. Provisional Patent application Ser. No.61/882,403, filed Sep. 25, 2013, the disclosures of which areincorporated by reference.

FIELD

This application relates in general to electrocardiographic monitoringand, in particular, to event alerting through actigraphy embedded withinelectrocardiographic data.

BACKGROUND

The heart emits electrical signals as a by-product of the propagation ofthe action potentials that trigger depolarization of heart fibers. Anelectrocardiogram (ECG) measures and records such electrical potentialsto visually depict the electrical activity of the heart over time.Conventionally, a standardized set format 12-lead configuration is usedby an ECG machine to record cardiac electrical signals fromwell-established traditional chest locations. Electrodes at the end ofeach lead are placed on the skin over the anterior thoracic region ofthe patient's body to the lower right and to the lower left of thesternum, on the left anterior chest, and on the limbs. Sensed cardiacelectrical activity is represented by PQRSTU waveforms that can beinterpreted post-ECG recordation to derive heart rate and physiology.The P-wave represents atrial electrical activity. The QRSTU componentsrepresent ventricular electrical activity.

An ECG is a tool used by physicians to diagnose heart problems and otherpotential health concerns. An ECG is a snapshot of heart function,typically recorded over 12 seconds, that can help diagnose rate andregularity of heartbeats, effect of drugs or cardiac devices, includingpacemakers and implantable cardioverter-defibrillators (ICDs), andwhether a patient has heart disease. ECGs are used in-clinic duringappointments, and, as a result, are limited to recording only thoseheart-related aspects present at the time of recording. Sporadicconditions that may not show up during a spot ECG recording requireother means to diagnose them. These disorders include fainting orsyncope; rhythm disorders, such as tachyarrhythmias andbradyarrhythmias; apneic episodes; and other cardiac and relateddisorders. Thus, an ECG only provides a partial picture and can beinsufficient for complete patient diagnosis of many cardiac disorders.

Diagnostic efficacy can be improved, when appropriate, through the useof long-term extended ECG monitoring. Recording sufficient ECG andrelated physiology over an extended period is challenging, and oftenessential to enabling a physician to identify events of potentialconcern. A 30-day observation period is considered the “gold standard”of ECG monitoring, yet achieving a 30-day observation period has provenunworkable because such ECG monitoring systems are arduous to employ,cumbersome to the patient, and excessively costly. Ambulatory monitoringin-clinic is implausible and impracticable. Nevertheless, if a patient'sECG could be recorded in an ambulatory setting, thereby allowing thepatient to engage in activities of daily living, the chances ofacquiring meaningful information and capturing an abnormal event whilethe patient is engaged in normal activities becomes more likely to beachieved.

For instance, the long-term wear of ECG electrodes is complicated byskin irritation and the inability ECG electrodes to maintain continualskin contact after a day or two. Moreover, time, dirt, moisture, andother environmental contaminants, as well as per ration, skin oil, anddead skin cells from the patient's body, can get between an ECGelectrode, the non-conductive adhesive used to adhere the ECG electrode,and the skin's surface. All of these factors adversely affect electrodeadhesion and the quality of cardiac signal recordings. Furthermore, thephysical movements of the patient and their clothing impart variouscompressional, tensile, and torsional forces on the contact point of anECG electrode, especially over long recording times, and an inflexiblyfastened ECG electrode will be prone to becoming dislodged.Notwithstanding the cause of electrode dislodgment, depending upon thetype of ECG monitor employed, precise re-placement of a dislodged ECGelectrode maybe essential to ensuring signal capture at the samefidelity. Moreover, dislodgment may occur unbeknownst to the patient,making the ECG recordings worthless. Further, some patients may haveskin that is susceptible to itching or irritation, and the wearing ofECG electrodes can aggravate such skin conditions. Thus, a patient maywant or need to periodically remove or replace ECG electrodes during along-term ECG monitoring period, whether to replace a dislodgedelectrode, reestablish better adhesion, alleviate itching or irritation,allow for cleansing of the skin, allow for showering and exercise, orfor other purpose. Such replacement or slight alteration in electrodelocation actually facilitates the goal of recording the ECG signal forlong periods of time.

Conventionally, Holter monitors are widely used for long-term extendedECG monitoring. Typically, they are used for only 24-48 hours. A typicalHolter monitor is a wearable and portable version of an ECG that includecables for each electrode placed on the skin and a separatebattery-powered ECG recorder. The cable and electrode combination (orleads) are placed in the anterior thoracic region in a manner similar towhat is done with an in-clinic standard ECG machine. The duration of aHolter monitoring recording depends on the sensing and storagecapabilities of the monitor, as well as battery life. A “looping” Holtermonitor (or event) can operate for a longer period of time byoverwriting older ECG tracings, thence “recycling” storage in favor ofextended operation, yet at the risk of losing event data. Althoughcapable of extended ECG monitoring, Holter monitors are cumbersome,expensive and typically only available by medical prescription, whichlimits their usability. Further, the skill required to properly placethe electrodes on the patient's chest hinders or precludes a patientfrom replacing or removing the precordial leads and usually involvesmoving the patient from the physician office to a specialized centerwithin the hospital or clinic. The relationship of cardiac events toactivity is crucial to proper diagnosis and patient management and thecorrelation of cardiac events to activity is a valuable patient caretool.

The ZIO XT Patch and ZIO Event Card devices, manufactured by iRhythmTech., Inc., San Francisco, Calif., are wearable stick-on monitoringdevices that are typically worn on the upper left pectoral region torespectively provide continuous and looping ECG recording. The locationis used to simulate surgically implanted monitors. Both of these devicesare prescription-only and for single patient use. The ZIO XT Patchdevice is limited to a 14-day monitoring period, while the electrodesonly of the ZIO Event Card device can be worn for up to 30 days. The ZIOXT Patch device combines both electronic recordation components,including battery, and physical electrodes into a unitary assembly thatadheres to the patient's skin. The ZIO XT Patch device uses adhesivesufficiently strong to support the weight of both the monitor and theelectrodes over an extended period of time and to resist disadherancefrom the patient's body, albeit at the cost of disallowing removal orrelocation during the monitoring period. Moreover, throughoutmonitoring, the battery is continually depleted and battery capacity canpotentially limit overall monitoring duration. The ZIO Event Card deviceis a form of downsized Holter monitor with a recorder component thatmust be removed temporarily during baths or other activities that coulddamage the non-waterproof electronics. Both devices representcompromises between length of wear and quality of ECG monitoring,especially with respect to ease of long term use, female-friendly fit,and quality of atrial (P-wave) signals.

The diagnosis, prognosis, and treatment of medical conditions can befurther improved by concomitant recording of ECG and human activity. Forinstance, the correlation of motor activity and cardiovascular stress isimportant for optimizing and monitoring exercise and rehabilitationprogress. Certain movement, such as a fall, may precipitate an episodeof heart disease; conversely, heart conditions may restrict a person'smovement or alter movement patterns.

An actigraphy sensor, such as an accelerometer, has conventionally beenused as a non-invasive method to monitor sleep, activity and movement.Sleep actigraphs are generally watch-shaped and worn on the wrist of thenon-dominant arm, and can be worn for weeks. Activity actigraphs areworn and used similar to a pedometer: around waist, near the hip. Theyare useful for determining the amount of activity and possibly calories.They can be worn for a number of days. Movement actigraphs are generallylarger and worn on the shoulder of the dominant arm. They contain 3-Dactigraph as opposed to a single dimension one used in sleep actigraphand activity actigraph, and tend to have a high sample rate and a largememory, as a result they are often used for only a few hours.

The correlation of ECG and movement is beneficial to patient care, andthe benefit increases with long-term monitoring. Wearing two separatedevices, one for ECG monitoring and another for actigraphy, however,creates its own problems. For example, recordings from two separatedevices are generally not synchronized. Also, a patient may misplace theactigraphy sensor, resulting in misinterpretation of movements. Forinstance, the SOMNOwatch actigraphy monitor, manufactured bySOMNOmedics, Randersacker, Germany, is a wearable watch-shapedmonitoring device that records sleep actigraphy and recognizessleep/wake rhythm, in addition to reading an ECG and recording heartrate. However, the SOMNOwatch actigraphy monitor can only store the rawdata of a single channel ECG for up to 18 hours, requires a softwaresystem to synchronize heart rate with motor activity, and does notrecord specific movement.

Therefore, a need remains for an extended wear continuously recordingECG monitor coupled with an actigraphy sensor practicably capable ofbeing worn for a long period of time and correlating cardiovascularevents with movements, in both men and women, and capable of recordingatrial signals reliably.

A further need remains for a device capable of recording signals idealfor arrhythmia discrimination, especially a device designed for atrialactivity recording in combination with actigraphy sensing.

SUMMARY

Physiological monitoring can be provided through a wearable monitor thatincludes two components, a flexible extended wear electrode patch and aremovable reusable monitor recorder. The wearable monitor sits centrally(in the midline) on the patient's chest along the sternum orientedtop-to-bottom. The placement of the wearable monitor in a location atthe sternal midline (or immediately to either side of the sternum), withits unique narrow “hourglass”-like shape, benefits long-term extendedwear by removing the requirement that ECG electrodes be continuallyplaced in the same spots on the skin throughout the monitoring period.Instead, the patient is free to place an electrode patch anywhere withinthe general region of the sternum, the area most likely to record highquality atrial signals or P-waves. In addition, the occurrence ofactigraphy events are monitored by the monitor recorder through anactigraphy sensor. Actigraphy becomes a recordable actigraphy eventoccurrence when the movement of the wearable monitor and, therefore, thepatient, exceeds a certain criteria threshold of acceleration ordeceleration as detected by the actigraphy sensor. Certain actigraphyevent occurrences as recorded by the monitor recorder are considered tobe actionable, that is, of sufficient importance to warrant flagging forfurther consideration to a following physician. For instance, theoccurrence of a fall event could signal the onset of myocardialinfarction in the patient, or, under different circumstances, could befound to have been precipitated by myocardial infarctional onset. Theoccurrence of an actigraphy event is identified as actionable based on afiltering criteria.

One embodiment provides an extended wear electrocardiography andphysiological sensor monitor recorder. A sealed housing is adapted to beremovably secured into the non-conductive receptacle on a disposableextended wear electrode patch. Electronic circuitry is included withinthe sealed housing. An externally-powered micro-controller is operableto execute under micro programmable control. An electrocardiographicfront end circuit is electrically interfaced to the micro-controller andis operable to sense electrocardiographic signals throughelectrocardiographic electrodes provided on the disposable extended wearelectrode patch. An actigraphy sensor is electrically interfaced withthe micro-controller and is operable to sense actigraphy eventoccurrences based on movement of the sealed housing using an actigraphyevent occurrence criteria. Externally-powered flash memory iselectrically interfaced with the micro-controller and is operable tostore samples of the electrocardiographic signals and samples of theactigraphy event occurrences.

A further embodiment provides an extended wear electrocardiography andphysiological sensor monitor. A disposable extended wear electrode patchincludes a flexible backing formed of an elongated strip of stretchablematerial with a narrow longitudinal midsection and, on each end. Acontact surface at least partially coated with an adhesive dressing isprovided as a crimp relief. A pair of electrocardiographic electrodes isconductively exposed on the contact surface of each end of the elongatedstrip. A non-conductive receptacle is adhered to an outward-facing endof the elongated strip and includes a plurality of electrical pads. Aflexible circuit is affixed on each end of the elongated strip as astrain relief and includes a pair of circuit traces electrically coupledto the pair of electrocardiographic electrodes and a pair of theelectrical pads. A reusable electrocardiography monitor has a sealedhousing adapted to be removably secured into the non-conductivereceptacle. A micro-controller is operable to execute under microprogrammable control and is electrically interfaced to anelectrocardiographic front end circuit that is operable to senseelectrocardiographic signals through the electrocardiographic electrodesvia the pair of electrical pads. An actigraphy sensor is electricallyinterfaced with the micro-controller and is operable to sense actigraphyevent occurrences based on movement of the sealed housing using anactigraphy event occurrence criteria. Flash memory is electricallyinterfaced with the micro-controller and is operable to store samples ofthe electrocardiographic signals and samples of the movement detected bythe actigraphy sensor.

The monitoring patch is especially suited to the female anatomy. Thenarrow longitudinal midsection can fit nicely within the intermammarycleft of the breasts without inducing discomfort, whereas conventionalpatch electrodes are wide and, if adhesed between the breasts, wouldcause chafing, irritation, frustration, and annoyance, leading to lowpatient compliance.

The foregoing aspects enhance ECG monitoring performance and quality,facilitating long-term ECG recording, critical to accurate arrhythmiadiagnosis.

In addition, the foregoing aspects enhance comfort in women (and certainmen), but not irritation of the breasts, by placing the monitoring patchin the best location possible for optimizing the recording of cardiacsignals from the atrium, another feature critical to proper arrhythmiadiagnosis.

Finally, the foregoing aspects as relevant to monitoring are equallyapplicable to recording other physiological measures, such astemperature, respiratory rate, blood sugar, oxygen saturation, and bloodpressure, as well as other measures of body chemistry and physiology.

Still other embodiments will become readily apparent to those skilled inthe art from the following detailed description, wherein are describedembodiments by way of illustrating the best mode contemplated. As willbe realized, other and different embodiments are possible and theembodiments' several details are capable of modifications in variousobvious respects, all without departing from their spirit and the scope.Accordingly, the drawings and detailed description are to be regarded asillustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are diagrams showing, by way of examples, an extended wearelectrocardiography and actigraphy monitor, including a monitor recorderin accordance with one embodiment, respectively fitted to the sternalregion of a female patient and a male patient.

FIG. 3 is a functional block diagram showing a system for remoteinterfacing of a combined ECG and actigraphy monitor recorder inaccordance with one embodiment inserted.

FIG. 4 is a perspective view showing an extended wear electrode patchwith the combined monitor recorder in accordance with one embodiment.

FIG. 5 is a perspective view showing the combined monitor recorder ofFIG. 4.

FIG. 6 is a perspective view showing the extended wear electrode patchof FIG. 4 without a monitor recorder inserted.

FIG. 7 is a bottom plan view of the monitor recorder of FIG. 4.

FIG. 8 is a top view showing the flexible circuit of the extended wearelectrode patch of FIG. 3 when mounted above the flexible backing

FIG. 9 is a functional block diagram showing the component architectureof the circuitry of the monitor recorder of FIG. 4.

FIG. 10 is a functional block diagram showing the circuitry of theextended wear electrode patch of FIG. 4.

FIG. 11 is a flow diagram showing a monitor recorder-implemented methodfor monitoring ECG data and actigraphy data for use in the monitorrecorder of FIG. 4.

FIG. 12 is a graph showing, by way of example, a typical ECG waveform.

FIG. 13 is a flow diagram showing a method for offloading and convertingECG and other physiological data from of an extended wearelectrocardiography and actigraphy monitor in accordance with oneembodiment.

FIG. 14 is a method 160 for processing data collected by the combinedECG and actigraphy monitor in accordance with one embodiment.

DETAILED DESCRIPTION

Physiological monitoring can be provided through a wearable monitor thatincludes two components, a flexible extended wear electrode patch and aremovable reusable monitor recorder. FIGS. 1 and 2 are diagrams showing,by way of examples, an extended wear electrocardiography andphysiological sensor monitor 12, including a monitor recorder 14 inaccordance with one embodiment, respectively fitted to the sternalregion of a female patient 10 and a male patient 11. The wearablemonitor 12 sits centrally (in the midline) on the patient's chest alongthe sternum 13 oriented top-to-bottom with the monitor recorder 14preferably situated towards the patient's head. In a further embodiment,the orientation of the wearable monitor 12 can be correctedpost-monitoring, as further described infra. The electrode patch 15 isshaped to fit comfortably and conformal to the contours of the patient'schest approximately centered on the sternal midline 16 (or immediatelyto either side of the sternum 13). The distal end of the electrode patch15 extends towards the Xiphoid process and, depending upon the patient'sbuild, may straddle the region over the Xiphoid process. The proximalend of the electrode patch 15, located under the monitor recorder 14, isbelow the manubrium and, depending upon patient's build, may straddlethe region over the manubrium.

The placement of the wearable monitor 12 in a location at the sternalmidline 16 (or immediately to either side of the sternum 13)significantly improves the ability of the wearable monitor 12 tocutaneously sense cardiac electric signals, particularly the P-wave (oratrial activity) and, to a lesser extent, the QRS interval signals inthe ECG waveforms that indicate ventricular activity whilesimultaneously facilitating comfortable long-term wear for many weeks.The sternum 13 overlies the right atrium of the heart and the placementof the wearable monitor 12 in the region of the sternal midline 13 putsthe ECG electrodes of the electrode patch 15 in a location betteradapted to sensing and recording P-wave signals than other placementlocations, say, the upper left pectoral region or lateral thoracicregion or the limb leads. In addition, placing the lower or inferiorpole (ECG electrode) of the electrode patch 15 over (or near) theXiphoid process facilitates sensing of ventricular activity and providessuperior recordation of the QRS interval.

When operated standalone, the monitor recorder 14 of the extended wearelectrocardiography and physiological sensor monitor 12 senses andrecords the patient's ECG data into an onboard memory. FIG. 3 is afunctional block diagram showing a system 120 for remote interfacing ofan extended wear electrocardiography and actigraphy sensor monitor 12 inaccordance with one embodiment. The monitor recorder 14 is a reusablecomponent that can be fitted during patient monitoring into anon-conductive receptacle provided on the electrode patch 15, as furtherdescribed infra with reference to FIG. 4, and later removed foroffloading of stored ECG data or to receive revised programming. Themonitor recorder 14 can then be connected to a download station 125,which could be a programmer or other device that permits the retrievalof stored ECG monitoring data, execution of diagnostics on orprogramming of the monitor recorder 14, or performance of otherfunctions. The monitor recorder 14 has a set of electrical contacts (notshown) that enable the monitor recorder 14 to physically interface to aset of terminals 128 on a paired receptacle 127 of the download station125. In turn, the download station 125 executes a communications oroffload program 126 (“Offload”) or similar program that interacts withthe monitor recorder 14 via the physical interface to retrieve thestored ECG monitoring data or to execute diagnostics on or reprogram themonitor recorder's program memory unit and thereby revise the subsequentoperation of the monitor recorder 14. The download station 125 could bea server, personal computer, tablet or handheld computer, smart mobiledevice, or purpose-built programmer designed specific to the task ofinterfacing with a monitor recorder 14. Still other forms of downloadstation 125 are possible. In addition, the wearable monitor 12 caninteroperate with other devices, as further described in detail incommonly-assigned U.S. patent application, entitled “Remote Interfacingof Extended Wear Electrocardiography and Physiological Sensor Monitor,”Ser. No. ______, filed ______, pending, the disclosure of which isincorporated by reference.

Upon retrieving stored ECG monitoring data from a monitor recorder 14,middleware first operates on the retrieved data to adjust the ECGcapture quality, as necessary, and to convert the retrieved data into aformat suitable for use by third party post-monitoring analysissoftware, as further described infra with reference to FIG. 13. Theformatted data can then be retrieved from the download station 125 overa hard link 135 using a control program 137 (“Ctl”) or analogousapplication executing on a personal computer 136 or other connectablecomputing device, via a communications link (not shown), whether wiredor wireless, or by physical transfer of storage media (not shown). Thepersonal computer 136 or other connectable device may also executemiddleware that converts ECG data and other information into a formatsuitable for use by a third-party post-monitoring analysis program, asfurther described infra with reference to FIG. 13. Note that formatteddata stored on the personal computer 136 would have to be maintained andsafeguarded in the same manner as electronic medical records (EMRs) 134in the secure database 124, as further discussed infra. In a furtherembodiment, the download station 125 is able to directly interface withother devices over a computer communications network 121, which could besome combination of a local area network and a wide area network,including the Internet, over a wired or wireless connection.

A client-server model could be used to employ a server 122 to remotelyinterface with the download station 125 over the network 121 andretrieve the formatted data or other information. The server 122executes a patient management program 123 (“Mgt”) or similar applicationthat stores the retrieved formatted data and other information in asecure database 124 cataloged in that patient's EMRs 134. In addition,the patient management program 123 could manage a subscription servicethat authorizes a monitor recorder 14 to operate for a set period oftime or under pre-defined operational parameters, such as described incommonly-assigned U.S. patent application, entitled “Self-AuthenticatingElectrocardiography Monitoring Circuit,” Ser. No. 14/082,066, filed Nov.15, 2013, pending, the disclosure of which is incorporated by reference.

The patient management program 123, or other trusted application, alsomaintains and safeguards the secure database 124 to limit access topatient EMRs 134 to only authorized parties for appropriate medical orother uses, such as mandated by state or federal law, such as under theHealth Insurance Portability and Accountability Act (HIPAA) or per theEuropean Union's Data Protection Directive. For example, a physician mayseek to review and evaluate his patient's ECG monitoring data, assecurely stored in the secure database 124. The physician would executean application program 130 (“Pgm”), such as a post-monitoring ECGanalysis program, on a personal computer 129 or other connectablecomputing device, and, through the application 130, coordinate access tohis patient's EMRs 134 with the patient management program 123. Otherschemes and safeguards to protect and maintain the integrity of patientEMRs 134 are possible.

During use, the electrode patch 15 is first adhesed to the skin alongthe sternal midline 16 (or immediately to either side of the sternum13). A monitor recorder 14 is then snapped into place on the electrodepatch 15 to initiate ECG monitoring. FIG. 4 is a perspective viewshowing an extended wear electrode patch 15 with a monitor recorder 14in accordance with one embodiment inserted. The body of the electrodepatch 15 is preferably constructed using a flexible backing 20 formed asan elongated strip 21 of wrap knit or similar stretchable material witha narrow longitudinal mid-section 23 evenly tapering inward from bothsides. A pair of cut-outs 22 between the distal and proximal ends of theelectrode patch 15 create a narrow longitudinal midsection 23 or“isthmus” and defines an elongated “hourglass”-like shape, when viewedfrom above.

The electrode patch 15 incorporates features that significantly improvewearability, performance, and patient comfort throughout an extendedmonitoring period. During wear, the electrode patch 15 is susceptible topushing, pulling, and torqueing movements, including compressional andtorsional forces when the patient bends forward, and tensile andtorsional forces when the patient leans backwards. To counter thesestress forces, the electrode patch 15 incorporates strain and crimpreliefs, such as described in commonly-assigned U.S. patent application,entitled “Extended Wear Electrocardiography Patch,” Ser. No. 14/080,717,filed Nov. 14, 2013, pending, the disclosure of which is incorporated byreference. In addition, the cut-outs 22 and longitudinal midsection 23help minimize interference with and discomfort to breast tissue,particularly in women (and gynecomastic men). The cut-outs 22 andlongitudinal midsection 23 further allow better conformity of theelectrode patch 15 to sternal bowing and to the narrow isthmus of flatskin that can occur along the bottom of the intermammary cleft betweenthe breasts, especially in buxom women. The cut-outs 22 and longitudinalmidsection 23 help the electrode patch 15 fit nicely between a pair offemale breasts in the intermammary cleft. Still other shapes, cut-outsand conformities to the electrode patch 15 are possible.

The monitor recorder 14 removably and reusably snaps into anelectrically non-conductive receptacle 25 during use. The monitorrecorder 14 contains electronic circuitry for recording and storing thepatient's electrocardiography as sensed via a pair of ECG electrodesprovided on the electrode patch 15, as further described infra beginningwith reference to FIG. 9, as well as described in commonly-assigned U.S.patent application, entitled “Extended Wear AmbulatoryElectrocardiography and Physiological Sensor Monitor,” Ser. No.14/080,725, filed Nov. 14, 2013, pending, the disclosure which isincorporated by reference. The non-conductive receptacle 25 is providedon the top surface of the flexible backing 20 with a retention catch 26and tension clip 27 molded into the non-conductive receptacle 25 toconformably receive and securely hold the monitor recorder 14 in place.

The monitor recorder 14 includes a sealed housing that snaps into placein the non-conductive receptacle 25. FIG. 5 is a perspective viewshowing the monitor recorder 14 of FIG. 4. The sealed housing 50 of themonitor recorder 14 intentionally has a rounded isoscelestrapezoidal-like shape 52, when viewed from above, such as described incommonly-assigned U.S. Design patent application, entitled“Electrocardiography Monitor,” Serial No. 29/472,046, filed Nov. 7,2013, pending, the disclosure of which is incorporated by reference. Theedges 51 along the top and bottom surfaces are rounded for patientcomfort. The sealed housing 50 is approximately 47 mm long, 23 mm wideat the widest point, and 7 mm high, excluding a patient-operabletactile-feedback button 55. The sealed housing 50 can be molded out ofpolycarbonate, ABS, or an alloy of those two materials. The button 55 iswaterproof and the button's top outer surface is molded silicon rubberor similar soft pliable material. A retention detent 53 and tensiondetent 54 are molded along the edges of the top surface of the housing50 to respectively engage the retention catch 26 and the tension clip 27molded into non-conductive receptacle 25. Other shapes, features, andconformities of the sealed housing 50 are possible.

The electrode patch 15 is intended to be disposable. The monitorrecorder 14, however, is reusable and can be transferred to successiveelectrode patches 15 to ensure continuity of monitoring. The placementof the wearable monitor 12 in a location at the sternal midline 16 (orimmediately on either side of the sternum 13) benefits long-termextended wear by removing the requirement that ECG electrodes becontinually placed in the same spots on the skin throughout themonitoring period. Instead, the patient is free to place an electrodepatch 15 anywhere within the general region of the sternum 13.

As a result, at any point during ECG monitoring, the patient's skin isable to recover from the wearing of an electrode patch 15, whichincreases patient comfort and satisfaction, while the monitor recorder14 ensures ECG monitoring continuity with minimal effort. A monitorrecorder 14 is merely unsnapped from a worn out electrode patch 15, theworn out electrode patch 15 is removed from the skin, a new electrodepatch 15 is adhered to the skin, possibly in a new spot immediatelyadjacent to the earlier location, and the same monitor recorder 14 issnapped into the new electrode patch 15 to reinitiate and continue theECG monitoring.

During use, the electrode patch 15 is first adhered to the skin in thesternal region. FIG. 6 is a perspective view showing the extended wearelectrode patch 15 of FIG. 4 without a monitor recorder 14 inserted. Aflexible circuit 32 is adhered to each end of the flexible backing 20. Adistal circuit trace 33 and a proximal circuit trace (not shown)electrically couple ECG electrodes (not shown) to a pair of electricalpads 34. The electrical pads 34 are provided within a moisture-resistantseal 35 formed on the bottom surface of the non-conductive receptacle25. When the monitor recorder 14 is securely received into thenon-conductive receptacle 25, that is, snapped into place, theelectrical pads 34 interface to electrical contacts (not shown)protruding from the bottom surface of the monitor recorder 14, and themoisture-resistant seal 35 enables the monitor recorder 14 to be worn atall times, even during bathing or other activities that could expose themonitor recorder 14 to moisture.

In addition, a battery compartment 36 is formed on the bottom surface ofthe non-conductive receptacle 25, and a pair of battery leads (notshown) electrically interface the battery to another pair of theelectrical pads 34. The battery contained within the battery compartment35 can be replaceable, rechargeable or disposable.

The monitor recorder 14 draws power externally from the battery providedin the non-conductive receptacle 25, thereby uniquely obviating the needfor the monitor recorder 14 to carry a dedicated power source. FIG. 7 isa bottom plan view of the monitor recorder 14 of FIG. 4. A cavity 58 isformed on the bottom surface of the sealed housing 50 to accommodate theupward projection of the battery compartment 36 from the bottom surfaceof the non-conductive receptacle 25, when the monitor recorder 14 issecured in place on the non-conductive receptacle 25. A set ofelectrical contacts 56 protrude from the bottom surface of the sealedhousing 50 and are arranged in alignment with the electrical pads 34provided on the bottom surface of the non-conductive receptacle 25 toestablish electrical connections between the electrode patch 15 and themonitor recorder 14. In addition, a seal coupling 57 circumferentiallysurrounds the set of electrical contacts 56 and securely mates with themoisture-resistant seal 35 formed on the bottom surface of thenon-conductive receptacle 25.

The placement of the flexible backing 20 on the sternal midline 16 (orimmediately to either side of the sternum 13) also helps to minimize theside-to-side movement of the wearable monitor 12 in the left- andright-handed directions during wear. To counter the dislodgment of theflexible backing 20 due to compressional and torsional forces, a layerof non-irritating adhesive, such as hydrocolloid, is provided at leastpartially on the underside, or contact, surface of the flexible backing20, but only on the distal end 30 and the proximal end 31. As a result,the underside, or contact surface of the longitudinal midsection 23 doesnot have an adhesive layer and remains free to move relative to theskin. Thus, the longitudinal midsection 23 forms a crimp relief thatrespectively facilitates compression and twisting of the flexiblebacking 20 in response to compressional and torsional forces. Otherforms of flexible backing crimp reliefs are possible.

Unlike the flexible backing 20, the flexible circuit 32 is only able tobend and cannot stretch in a planar direction. The flexible circuit 32can be provided either above or below the flexible backing 20. FIG. 8 isa top view showing the flexible circuit 32 of the extended wearelectrode patch 15 of FIG. 4 when mounted above the flexible backing 20.A distal ECG electrode 38 and proximal ECG electrode 39 are respectivelycoupled to the distal and proximal ends of the flexible circuit 32. Astrain relief 40 is defined in the flexible circuit 32 at a locationthat is partially underneath the battery compartment 36 when theflexible circuit 32 is affixed to the flexible backing 20. The strainrelief 40 is laterally extendable to counter dislodgment of the ECGelectrodes 38, 39 due to tensile and torsional forces. A pair of strainrelief cutouts 41 partially extend transversely from each opposite sideof the flexible circuit 32 and continue longitudinally towards eachother to define in ‘S’-shaped pattern, when viewed from above. Thestrain relief respectively facilitates longitudinal extension andtwisting of the flexible circuit 32 in response to tensile and torsionalforces. Other forms of circuit board strain relief are possible.

ECG monitoring and other functions performed by the monitor recorder 14are provided through a micro controlled architecture. FIG. 9 is afunctional block diagram showing the component architecture of thecircuitry 60 of the monitor recorder 14 of FIG. 4. The circuitry 60 isexternally powered through a battery provided in the non-conductivereceptacle 25 (shown in FIG. 6). Both power and raw ECG signals, whichoriginate in the pair of ECG electrodes 38, 39 (shown in FIG. 8) on thedistal and proximal ends of the electrode patch 15, are received throughan external connector 65 that mates with a corresponding physicalconnector on the electrode patch 15. The external connector 65 includesthe set of electrical contacts 56 that protrude from the bottom surfaceof the sealed housing 50 and which physically and electrically interfacewith the set of pads 34 provided on the bottom surface of thenon-conductive receptacle 25. The external connector includes electricalcontacts 56 for data download, microcontroller communications, power,analog inputs, and a peripheral expansion port. The arrangement of thepins on the electrical connector 65 of the monitor recorder 14 and thedevice into which the monitor recorder 14 is attached, whether anelectrode patch 15 or download station (not shown), follow the sameelectrical pin assignment convention to facilitate interoperability. Theexternal connector 65 also serves as a physical interface to a downloadstation that permits the retrieval of stored ECG monitoring data,communication with the monitor recorder 14, and performance of otherfunctions.

Operation of the circuitry 60 of the monitor recorder 14 is managed by amicrocontroller 61. The micro-controller 61 includes a program memoryunit containing internal flash memory that is readable and writeable.The internal flash memory can also be programmed externally. Themicro-controller 61 draws power externally from the battery provided onthe electrode patch 15 via a pair of the electrical contacts 56. Themicrocontroller 61 connects to the ECG front end circuit 63 thatmeasures raw cutaneous electrical signals and generates an analog ECGsignal representative of the electrical activity of the patient's heartover time.

The circuitry 60 of the monitor recorder 14 also includes a flash memory62, which the micro-controller 61 uses for storing ECG monitoring dataand other physiology and information. The flash memory 62 also drawspower externally from the battery provided on the electrode patch 15 viaa pair of the electrical contacts 56. Data is stored in a serial flashmemory circuit, which supports read, erase and program operations over acommunications bus. The flash memory 62 enables the microcontroller 61to store digitized ECG data. The communications bus further enables theflash memory 62 to be directly accessed externally over the externalconnector 65 when the monitor recorder 14 is interfaced to a downloadstation.

The circuitry 60 of the monitor recorder 14 further includes anactigraphy sensor 64 implemented as a 3-axis accelerometer. Theaccelerometer may be configured to generate interrupt signals to themicrocontroller 61 by independent initial wake up and free fall events,as well as by device position. During ECG monitoring, actigraphy becomesa recordable actigraphy event occurrence when the movement of thewearable monitor 12 and, therefore, the patient, exceeds a certaincriteria threshold of acceleration or deceleration as detected by theactigraphy sensor 64, as further described infra with reference to FIG.11. In addition, the actigraphy provided by the accelerometer can beused during post-monitoring analysis to correct the orientation of themonitor recorder 14 if, for instance, the monitor recorder 14 has beeninadvertently installed upside down, that is, with the monitor recorder14 oriented on the electrode patch 15 towards the patient's feet, aswell as for other event occurrence analyses.

The microcontroller 61 includes an expansion port that also utilizes thecommunications bus. External devices, separately drawing powerexternally from the battery provided on the electrode patch 15 or othersource, can interface to the microcontroller 61 over the expansion portin half duplex mode. For instance, an external physiology sensor can beprovided as part of the circuitry 60 of the monitor recorder 14, or canbe provided on the electrode patch 15 with communication with themicro-controller 61 provided over one of the electrical contacts 56. Thephysiology sensor can include an SpO₂ sensor, blood pressure sensor,temperature sensor, respiratory rate sensor, glucose sensor, airflowsensor, volumetric pressure sensing, or other types of sensor ortelemetric input sources. For instance, the integration of an airflowsensor is described in commonly-assigned U.S. patent application,entitled “Self-Contained Personal Air Flow Sensing Monitor,” Ser. No.14/082,102, filed Nov. 15, 2013, pending, the disclosure which isincorporated by reference. In a further embodiment, a wireless interfacefor interfacing with other wearable (or implantable) physiologymonitors, as well as data offload and programming, can be provided aspart of the circuitry 60 of the monitor recorder 14, or can be providedon the electrode patch 15 with communication with the micro-controller61 provided over one of the electrical contacts 56, such as described incommonly-assigned U.S. patent application, entitled “Remote Interfacingof Extended Wear Electrocardiography and Physiological Sensor Monitor,”Ser. No. 14/082,071, filed Nov. 15, 2013, pending, the disclosure ofwhich is incorporated by reference.

Finally, the circuitry 60 of the monitor recorder 14 includespatient-interfaceable components, including a tactile feedback button66, which a patient can press to mark events or to perform otherfunctions, and a buzzer 67, such as a speaker, magnetic resonator orpiezoelectric buzzer. The buzzer 67 can be used by the microcontroller61 to output feedback to a patient such as to confirm power up andinitiation of ECG monitoring. Still other components as part of thecircuitry 60 of the monitor recorder 14 are possible, such as describedin commonly-assigned U.S. patent application, entitled “Extended WearAmbulatory Electrocardiography and Physiological Sensor Monitor,” Ser.No. 14/080,725, filed Nov. 14, 2013, pending, the disclosure which isincorporated by reference.

While the monitor recorder 14 operates under micro control, most of theelectrical components of the electrode patch 15 operate passively. FIG.10 is a functional block diagram showing the circuitry 70 of theextended wear electrode patch 15 of FIG. 4. The circuitry 70 of theelectrode patch 15 is electrically coupled with the circuitry 60 of themonitor recorder 14 through an external connector 74. The externalconnector 74 is terminated through the set of pads 34 provided on thebottom of the non-conductive receptacle 25, which electrically mate tocorresponding electrical contacts 56 protruding from the bottom surfaceof the sealed housing 50 to electrically interface the monitor recorder14 to the electrode patch 15.

The circuitry 70 of the electrode patch 15 performs three primaryfunctions. First, a battery 71 is provided in a battery compartmentformed on the bottom surface of the non-conductive receptacle 25. Thebattery 71 is electrically interfaced to the circuitry 60 of the monitorrecorder 14 as a source of external power. The unique provisioning ofthe battery 71 on the electrode patch 15 provides several advantages.First, the locating of the battery 71 physically on the electrode patch15 lowers the center of gravity of the overall wearable monitor 12 andthereby helps to minimize shear forces and the effects of movements ofthe patient and clothing. Moreover, the housing 50 of the monitorrecorder 14 is sealed against moisture and providing power externallyavoids having to either periodically open the housing 50 for the batteryreplacement, which also creates the potential for moisture intrusion andhuman error, or to recharge the battery, which can potentially take themonitor recorder 14 off line for hours at a time. In addition, theelectrode patch 15 is intended to be disposable, while the monitorrecorder 14 is a reusable component. Each time that the electrode patch15 is replaced, a fresh battery is provided for the use of the monitorrecorder 14, which enhances ECG monitoring performance quality andduration of use. Finally, the architecture of the monitor recorder 14 isopen, in that other physiology sensors or components can be added byvirtue of the expansion port of the microcontroller 61. Requiring thoseadditional sensors or components to draw power from a source external tothe monitor recorder 14 keeps power considerations independent of themonitor recorder 14. Thus, a battery of higher capacity could beintroduced when needed to support the additional sensors or componentswithout effecting the monitor recorders circuitry 60.

Second, the pair of ECG electrodes 38, 39 respectively provided on thedistal and proximal ends of the flexible circuit 32 are electricallycoupled to the set of pads 34 provided on the bottom of thenon-conductive receptacle 25 by way of their respective circuit traces33, 37. The signal ECG electrode 39 includes a protection circuit 72,which is an inline resistor that protects the patient from excessiveleakage current.

Last, in a further embodiment, the circuitry 70 of the electrode patch15 includes a cryptographic circuit 73 to authenticate an electrodepatch 15 for use with a monitor recorder 14. The cryptographic circuit73 includes a device capable of secure authentication and validation.The cryptographic device 73 ensures that only genuine, non-expired,safe, and authenticated electrode patches 15 are permitted to providemonitoring data to a monitor recorder 14, such as described incommonly-assigned U.S. patent application, entitled “Self-AuthenticatingElectrocardiography Monitoring Circuit,” Ser. No. 14/082,066, filed Nov.15, 2013, pending, the disclosure which is incorporated by reference.

The monitor recorder 14 continuously monitors the patient's heart rateand physiology. FIG. 11 is a flow diagram showing a monitorrecorder-implemented method 100 for monitoring ECG data for use in themonitor recorder 14 of FIG. 4. Initially, upon being connected to theset of pads 34 provided with the non-conductive receptacle 25 when themonitor recorder 14 is snapped into place, the microcontroller 61executes a power up sequence (step 101). During the power up sequence,the voltage of the battery 71 is checked, the state of the flash memory62 is confirmed, both in terms of operability check and availablecapacity, and microcontroller operation is diagnostically confirmed. Ina further embodiment, an authentication procedure between themicrocontroller 61 and the electrode patch 15 are also performed.

Following satisfactory completion of the power up sequence, an iterativeprocessing loop (steps 102-109) is continually executed by themicrocontroller 61. During each iteration (step 102) of the processingloop, the ECG frontend 63 (shown in FIG. 9) continually senses thecutaneous ECG electrical signals (step 103) via the ECG electrodes 38,29 and is optimized to maintain the integrity of the P-wave. A sample ofthe ECG signal is read (step 104) by the microcontroller 61 by samplingthe analog ECG signal output front end 63. FIG. 12 is a graph showing,by way of example, a typical ECG waveform 110. The x-axis representstime in approximate units of tenths of a second. The y-axis representscutaneous electrical signal strength in approximate units of millivolts.The P-wave 111 has a smooth, normally upward, that is, positive,waveform that indicates atrial depolarization. The QRS complex usuallybegins with the downward deflection of a Q-wave 112, followed by alarger upward deflection of an R-wave 113, and terminated with adownward waveform of the S-wave 114, collectively representative ofventricular depolarization. The T-wave 115 is normally a modest upwardwaveform, representative of ventricular depolarization, while the U-wave116, often not directly observable, indicates the recovery period of thePurkinje conduction fibers.

Sampling of the R-to-R interval enables heart rate informationderivation. For instance, the R-to-R interval represents the ventricularrate and rhythm, while the P-to-P interval represents the atrial rateand rhythm. Importantly, the PR interval is indicative ofatrioventricular (AV) conduction time and abnormalities in the PRinterval can reveal underlying heart disorders, thus representinganother reason why the P-wave quality achievable by the extended wearambulatory electrocardiography and physiological sensor monitordescribed herein is medically unique and important. The long-termobservation of these ECG indicia, as provided through extended wear ofthe wearable monitor 12, provides valuable insights to the patient'scardiac function and overall well-being.

Each sampled ECG signal, in quantized and digitized form, is temporarilystaged in buffer (step 105), pending compression preparatory to storagein the flash memory 62 (step 106). Following compression, the compressedECG digitized sample is again buffered (step 107), then written to theflash memory 62 (step 108) using the communications bus. Processingcontinues (step 109), so long as the monitoring recorder 14 remainsconnected to the electrode patch 15 (and storage space remains availablein the flash memory 62), after which the processing loop is exited andexecution terminates. Still other operations and steps are possible.

The monitor recorder 14 also receives data from the actigraphy sensor64. The data is received in a conceptually-separate execution thread aspart of the iterative processing loop (step 102-109) continuallyexecuted by the micro-controller 61. During each iteration (step 102) ofthe processing loop, the actigraphy sensor 64 monitors a patient'smovement and detects if there is a notable movement event, such as anevent that may trigger or reflect a cardiovascular episode, that needsto be recorded as part of the monitoring (step 140). One example of anotable movement is a fall. When a patient sits still in a chair, anaccelerometer records a g-force (g) equivalent to 1 g along the axisperpendicular towards the earth. If the patient falls from the chair,the accelerometer records a g-force equivalent to zero, or very close tozero, along the axis perpendicular towards the earth, during thefreefall. Another example of a notable movement is a sudden accelerationor deceleration that is indicative of a forceful, traumatic impact on apatient, in which the g-force along at least one axis exceeds a certainthreshold, for example, 2.5 g. Still another example is a series ofaccelerations and decelerations exceeding a certain threshold ofg-force, indicating intensive physical exertions that may put unduestresses to heart. Other examples are possible. If no such notablemovement events are detected, the method 100 proceeds to step 109. If anotable movement event is detected, the actigraphy sensor 64 provides aninterrupt signal to the microprocessor 61, and the microprocessor 61reads the data sample that includes the movement event and converts intoa digital signal by the onboard ADC of the microcontroller 61 (step141). This design provides an automatic time-correlation between amovement event and its corresponding ECG data. No additional software isneeded to synchronize the accelerometer data and ECG data, resulting anefficient monitor recorder 14 and simplified post-recording processing.

During each iteration (step 102) of the processing loop, if movementdata is detected (step 140), a sample of the movement telemetry is read(step 141) by the microcontroller 61 and, if necessary, converted into adigital signal by the onboard ADC of the microcontroller 61. Eachsampled movement event, in quantized and digitized form, is temporarilystaged in buffer (step 142), tending compression preparatory to storagein the flash memory subsystem 62 (step 143). Following compression, thecompressed digitized movement sample is again buffered (step 144), thenwritten to the flash memory subsystem 62 (step 145) using thecommunications bus. Processing continues (step 109), so long as themonitoring recorder 14 remains connected to the electrode patch 15 (andstorage space remains available in the flash memory 62), after which theprocessing loop is exited and execution terminates. Still otheroperations and steps are possible.

The monitor recorder 14 stores ECG data and other information in theflash memory subsystem 62 (shown in FIG. 9) using a proprietary formatthat includes data compression. As a result, data retrieved from amonitor recorder 14 must first be converted into a format suitable foruse by third party post-monitoring analysis software. FIG. 13 is a flowdiagram showing a method 150 for offloading and converting ECG and otherphysiological data from an extended wear electrocardiography andphysiological sensor monitor 12 in accordance with one embodiment. Themethod 150 can be implemented in software and execution of the softwarecan be performed on a download station 125, which could be a programmeror other device, or a computer system, including a server 122 orpersonal computer 129, such as further described supra with reference toFIG. 3, as a series of process or method modules or steps. Forconvenience, the method 150 will be described in the context of beingperformed by a personal computer 136 or other connectable computingdevice (shown in FIG. 3) as middleware that converts ECG data and otherinformation into a format suitable for use by a third-partypost-monitoring analysis program. Execution of the method 150 by othercomputer system or download station 125 would be analogous mutatismutandis.

Initially, the download station 125 is connected to the monitor recorder14 (step 151), such as by physically interfacing to a set of terminals128 on a paired receptacle 127 or by wireless connection, if available.The data stored on the monitor recorder 14, including ECG andphysiological monitoring data, other recorded data, and otherinformation are retrieved (step 152) over a hard link 135 using acontrol program 137 (“Ctl”) or analogous application executing on apersonal computer 136 or other connectable computing device.

The data retrieved from the monitor recorder 14 is in a proprietarystorage format and each datum of recorded ECG monitoring data, as wellas any other physiological data or other information, must be converted,so that the data can be used by a third-party post-monitoring analysisprogram. Each datum of ECG monitoring data is converted by themiddleware (steps 153-159) in an iterative processing loop. During eachiteration (step 153), the ECG datum is read (step 154) and, ifnecessary, the gain of the ECG signal is adjusted (step 155) tocompensate, for instance, for relocation or replacement of the electrodepatch 15 during the monitoring period.

In addition, depending upon the configuration of the wearable monitor12, other physiological data (or other information), including patientevents, such as a fall, peak activity level, sleep detection, detectionof patient activity levels and states, and so on, may be recorded alongwith the ECG monitoring data. For instance, actigraphy data may havebeen sampled by the actigraphy sensor 64 based on a sensed eventoccurrence, such as a sudden change in orientation due to the patienttaking a fall. In response, the monitor recorder 14 will embed theactigraphy data samples into the stream of data, including ECGmonitoring data, that is recorded to the flash memory 62 by themicro-controller 61. Post-monitoring, the actigraphy data is temporallymatched to the ECG data to provide the proper physiological context tothe sensed event occurrence. As a result, the three-axis actigraphysignal is turned into an actionable event occurrence that is provided,through conversion by the middleware, to third party post-monitoringanalysis programs, along with the ECG recordings contemporaneous to theevent occurrence. Other types of processing of the other physiologicaldata (or other information) are possible.

In a further embodiment, other physiological data recorded is also read(step 156) and is time-correlated to the ECG monitoring data. Forinstance, blood pressure recorded by a blood pressure sensor would betemporally matched to the monitoring ECG data to provide the properphysiological context to the sensed event occurrence. Other types ofprocessing of the other physiological data are possible.

Thus, during execution of the middleware, any other physiological data(or other information) that has been embedded into the recorded ECGmonitoring data is read (step 156) and time-correlated to the time frameof the ECG signals that occurred at the time that the otherphysiological data (or other information) was noted (step 157). Finally,the ECG datum, signal gain adjusted, if appropriate, and otherphysiological data, if applicable and as time-correlated, are stored ina format suitable to the backend software (step 158) used inpost-monitoring analysis.

In a further embodiment, the other physiological data, if apropos, isembedded within an unused ECG track. For example, the SCP-ENG standardallows multiple ECG channels to be recorded into a single ECG record.The monitor recorder 14, though, only senses one ECG channel. The otherphysiological data can be stored into an additional ECG channel, whichwould otherwise be zero-padded or altogether omitted. One example of theother physiological data is actigraphy data. The backend software wouldthen be able to read the other physiological data in context with thesingle channel of ECG monitoring data recorded by the monitor recorder14, provided the backend software implemented changes necessary tointerpret the other physiological data. Still other forms of embeddingof the other physiological data with formatted ECG monitoring data, orof providing the other physiological data in a separate manner, arepossible.

Processing continues (step 159) for each remaining ECG datum, afterwhich the processing loop is exited and execution terminates. Stillother operations and steps are possible.

The occurrence of actigraphy events are monitored by the monitorrecorder 14 through the actigraphy sensor 64 of the circuitry 60 (shownin FIG. 9). The data collected by the monitor recorder 14 can be furtherprocessed by the application software to correlate the actigraphy eventoccurrences with ECG and other non-movement physiological data, ifapplicable. FIG. 14 is a flow diagram showing a method 160 forprocessing actigraphy data collected by a monitor recorder 14 inaccordance with one embodiment. Physiological data includes actigraphydata, ECG monitoring data and, if applicable, other physiological data.Physiological data is offloaded and converted as described supra withreference to FIG. 13. The converted physiological data is then retrievedby the backend software (step 161). The backend software processes theretrieved physiological data to identify recorded actigraphy eventoccurrences (step 162).

During ECG monitoring, actigraphy becomes a recordable actigraphy eventoccurrence when the movement of the wearable monitor 12 and, therefore,the patient, exceeds a certain criteria threshold of acceleration ordeceleration as detected by the actigraphy sensor 64. Ordinarily,movement of a patient is continual, but, for the most part, not risingto the level of an event occurrence. For instance, the rise and fall ofa patient's chest attendant to regular breathing constitutes movement,yet such movement is ordinary and expected. Recording each occurrence ofordinary and expected movement of this sort is not necessary, and theactigraphy sensor 64 would be set per a stored criteria to ignore thosemovement failing to warrant recordation (as event occurrences) throughonboard parameters that specify the conditions under which actigraphywill be recorded as event occurrences, such as described supra withreference to FIG. 11. For instance, the onboard parameters could be setto trigger actigraphy recordation when the g-force along at least oneaxis exceeds a certain criteria threshold, for example, 2.5 g, althoughother thresholds could be used. However, when a patient appears to havefallen, the movement of the patient will be both sudden and relativelydramatic in comparison to, say, regular breathing. Such movement will berecorded as an actigraphy event occurrence.

In addition, certain actigraphy event occurrences are considered to beactionable, that is, of sufficient importance to warrant flagging forfurther consideration to a following physician. For instance, theoccurrence of a fall event could signal the onset of myocardialinfarction in the patient, or, under different circumstances, could befound to have been precipitated by myocardial infarctional onset. Theoccurrence of an actigraphy event is identified as actionable based on afiltering criteria. Actionable actigraphy event occurrences include, forinstance, sleep, awake, hyperactivity, and falling, although otheractionable actigraphy event occurrences are possible. Both theoccurrence of the actigraphy event, that is, the fall, and the patient'sECG monitoring data, as well as any other available physiological data,may be of diagnostic interest and are identified (step 163). In turn, aphysician would scrutinize the identified physiological data, includingthe ECG monitoring data and the actigraphy event occurrence, foraccompanying indications of myocardial infarction, or other concernsrelating to syncope and related maladies.

Other types of physiological data may include data recorded by otherphysiology sensors including the SpO₂ sensor, blood pressure sensor,temperature sensor, glucose sensor, airflow sensor, volumetric pressuresensing, or other types of sensor or telemetric input sources. In thisexample, is a blood pressure sensor were available to record bloodpressure substantially concurrent to the monitoring of ECG andactigraphy, the retrieved blood pressure data would be temporallyaligned with the physiological data relating to the patient's fall andthereby help to diagnostic efficacy. Optionally, these otherphysiological data may be processed according to diagnostic andprognostic values of the data (step 164). Finally, the information aboutthe actigraphy events, such as the time the events occurred, theduration of the events, the nature of the event (intensity of the fall,for example), together with the other approximately physiological datarelevant for diagnosis, are output for consultation by a physician oranother medical professional (step 165). Still other operations andsteps are possible. Other types of processing the other physiologicaldata are possible.

While the invention has been particularly shown and described asreferenced to the embodiments thereof, those skilled in the art willunderstand that the foregoing and other changes in form and detail maybe made therein without departing from the spirit and scope.

1. An extended wear electrocardiography and physiological sensor monitorrecorder, comprising: a sealed housing adapted to be removably securedinto the non-conductive receptacle on a disposable extended wearelectrode patch; and an electronic circuitry comprised within the sealedhousing, comprising: an externally-powered micro-controller operable toexecute under micro programmable control; an electrocardiographic frontend circuit electrically interfaced to the micro-controller and operableto sense electrocardiographic signals through electrocardiographicelectrodes provided on the disposable extended wear electrode patch,each of the electrocardiographic electrodes adapted to be positionedaxially along the midline of the sternum for capturing action potentialpropagation; an actigraphy sensor electrically interfaced with themicro-controller and operable to sense actigraphy event occurrencesbased on movement of the sealed housing using an actigraphy eventoccurrence criteria; and an externally-powered flash memory electricallyinterfaced with the micro-controller and operable to store samples ofthe electrocardiographic signals and samples of the actigraphy eventoccurrences.
 2. An electrocardiography and physiological sensor monitorrecorder according to claim 1, further comprising: a server computersystem centrally accessible over a data communications network andcomprising a processor configured to execute program code stored in amemory, comprising: a data retrieval module configured to retrieve thesamples of the electrocardiographic signals and the samples of theactigraphy event occurrences from the flash memory of the electroniccircuitry; an evaluation module configured to identify an actionableactigraphy event occurrence from the samples of the actigraphy eventoccurrences based on a filtering criteria; a correlation moduleconfigured to identify those samples of the electrocardiographic signalsthat were sensed substantially concurrent to a time of the occurrence ofthe actionable actigraphy event; and an output module configured tooutput the actionable event occurrence and the samples of theelectrocardiographic signals that were identified.
 3. Anelectrocardiography and physiological sensor monitor recorder accordingto claim 2, wherein the actigraphy event occurrence criteria comprises athreshold of acceleration or deceleration of the sealed housing.
 4. Anelectrocardiography and physiological sensor monitor recorder accordingto claim 3, wherein the threshold of acceleration or deceleration of thesealed housing is expressed based on recorded g-force.
 5. Anelectrocardiography and physiological sensor monitor recorder accordingto claim 2, wherein the filtering criteria is selected from the groupcomprising sleep, awake, hyperactivity, and falling.
 6. Anelectrocardiography and physiological sensor monitor recorder accordingto claim 2, further comprising: a three-axis accelerometer comprised inthe actigraphy sensor, the actigraphy event occurrence criteriacomprising a threshold of acceleration or deceleration along at leastone of the axes of the three-axis accelerometer.
 7. Anelectrocardiography and physiological sensor monitor recorder accordingto claim 2, further comprising: a data retrieval module furtherconfigured to retrieve samples of physiology selected from the groupcomprising SpO₂, blood pressure, temperature, glucose level, air flow,and volumetric pressure.
 8. An extended wear electrocardiography andphysiological sensor monitor, comprising: a disposable extended wearelectrode patch comprising: a flexible backing formed of an elongatedstrip of stretchable material with a narrow longitudinal midsection and,on each end, a contact surface at least partially coated with anadhesive dressing provided as a crimp relief; a pair ofelectrocardiographic electrodes conductively exposed on the contactsurface of each end of the elongated strip, respectively; anon-conductive receptacle adhered to an outward-facing surface of theelongated strip and comprising a plurality of electrical pads; and aflexible circuit affixed on each end of the elongated strip as a strainrelief and comprising a pair of circuit traces electrically coupled tothe pair of electrocardiographic electrodes and a pair of the electricalpads, at least one of the circuit traces adapted to extend along thenarrow longitudinal midsection to serve as the strain relief; and areusable electrocardiography monitor having a sealed housing adapted tobe removably secured into the non-conductive receptacle and comprising:a micro-controller operable to execute under micro programmable controland electrically interfaced to an electrocardiographic front end circuitthat is operable to sense electrocardiographic signals through theelectrocardiographic electrodes via the pair of the electrical pads; anactigraphy sensor electrically interfaced with the micro-controller andoperable to sense actigraphy event occurrences based on movement of thesealed housing using an actigraphy event occurrence criteria; and flashmemory electrically interfaced with the micro-controller and operable tostore samples of the electrocardiographic signals and samples ofactigraphy event occurrences detected by the actigraphy sensor.
 9. Anextended wear electrocardiography and physiological sensor monitoraccording to claim 8, wherein the electrocardiographic front end circuitis optimized to sense P-wave signals in the electrocardiographicsignals.
 10. An extended wear electrocardiography and physiologicalsensor monitor according to claim 8, further comprising: a servercomputer system centrally accessible over a data communications networkand comprising a processor configured to execute program code stored ina memory, comprising: a data retrieval module configured to retrieve thesamples of the electrocardiographic signals and the samples of theactigraphy event occurrences from the flash memory of the electroniccircuitry; an evaluation module configured to identify an actionableactigraphy event occurrence from the samples of the actigraphy eventoccurrences based on a filtering criteria; a correlation moduleconfigured to identify those samples of the electrocardiographic signalsthat were sensed substantially concurrent to a time of the occurrence ofthe actionable actigraphy event; and an output module configured tooutput the actionable event occurrence and the samples of theelectrocardiographic signals that were identified.
 11. An extended wearelectrocardiography and physiological sensor monitor according to claim10, wherein the actigraphy event occurrence criteria comprises athreshold of acceleration or deceleration of the sealed housing.
 12. Anextended wear electrocardiography and physiological sensor monitoraccording to claim 11, wherein the threshold of acceleration ordeceleration of the sealed housing is expressed based on recordedg-force.
 13. An extended wear electrocardiography and physiologicalsensor monitor according to claim 10, wherein the filtering criteria isselected from the group comprising sleep, awake, hyperactivity, andfalling.
 14. An extended wear electrocardiography and physiologicalsensor monitor according to claim 10, further comprising: a three-axisaccelerometer comprised in the actigraphy sensor, the actigraphy eventoccurrence criteria comprising a threshold of acceleration ordeceleration along at least one of the axes of the three-axisaccelerometer.
 15. An extended wear electrocardiography andphysiological sensor monitor according to claim 8, further comprising: abattery comprised on the disposable extended wear electrode patch andelectrically interfaced via battery leads to a pair of the electricalpads; and at least one of: the micro-controller operable to draw powerfrom the battery via the pair of the electrical pads; and the flashmemory operable to draw power from the battery via the pair of theelectrical pads.
 16. An extended wear electrocardiography andphysiological sensor monitor according to claim 8, further comprising:an expansion bus operatively interconnected to the micro-controller andelectrically coupled to at least one of the electrical pads; aphysiology sensor comprised within the disposable extended wearelectrode patch and operable to sense physiology and to draw power fromthe battery via the battery leads, the physiology sensor electricallyinterfaced with the micro-controller over the expansion bus; and theflash memory further operable through the expansion bus to store samplesof the physiology sensed by the physiology sensor.
 17. An extended wearelectrocardiography and physiological sensor monitor according to claim16, wherein the physiology sensor is selected from the group comprisingan SpO₂ sensor, a blood pressure sensor, a temperature sensor, arespiratory rate sensor, a glucose sensor, an air flow sensor, and avolumetric pressure sensor.
 18. An extended wear electrocardiography andphysiological sensor monitor according to claim 8, further comprising:an expansion bus operatively interconnected to the micro-controller; aphysiology sensor comprised within the reusable electrocardiographymonitor and operable to sense physiology and to draw power from thebattery via the pair of the electrical pads, the physiology sensorelectrically interfaced with the micro-controller over the expansionbus; and the flash memory further operable through the expansion bus tostore samples of the physiology sensed detected by the physiologysensor.
 19. An extended wear electrocardiography and physiologicalsensor monitor according to claim 18, wherein the physiology sensor isselected from the group comprising an SpO₂ sensor, a blood pressuresensor, a temperature sensor, a respiratory rate sensor, a glucosesensor, an air flow sensor, and a volumetric pressure sensor.
 20. Anextended wear electrocardiography and physiological sensor monitoraccording to claim 8, further comprising at least one of: a feedbackoutput component comprised in the reusable electrocardiography monitorand electrically interfaced with the micro-controller; and a feedbackinput component comprised in the reusable electrocardiography monitorand externally wearer-operable from outside the sealed housing, thefeedback input further electrically interfaced with themicro-controller.